Right off the bat, the height of the fighting compartment isn't enough for the loader. The manual recommends 1750-1800 mm, but the included diagram shows that this requirement wasn't met by any WWII era tanks. 1620 mm provided by the SG-122 is still a lot, beaten only by the Churchill, the Cromwell, and the PzIII.
The line marking the bore axis is also visible in the image, which makes it easy to figure out its height: 1260 mm. This is rather high. At this height, the manual suggests that the breech should be horizontal, pointed towards the loader. However, since the M-30 howitzer uses a screw breech instead of a sliding breech as assumed by the manual, this advice doesn't really apply.
Via Yuri Pasholok.